Producing reservoir wells involves drilling subsurface formations and monitoring various subsurface formation parameters. Drilling and monitoring typically involves using downhole tools having high-power electronic devices. During operation, the electronic devices generate heat that often builds up in a downhole tool. The built up heat can be detrimental to the operation of the downhole tool. A traditional technique for dissipating the heat involves using heat sinks in a downhole tool. Another traditional technique involves using evaporation-condensation cycle heat pipes that use passive flow capillary action to carry heat away from a heat source. In an evaporation-condensation cycle, a fluid in a closed loop heat pipe evaporates when it draws heat. In the gaseous state, the vapor carries the heat away using passive flow capillary action. Upon cooling, the vapor condenses into a fluid, which can again be evaporated to transfer additional heat in the gaseous state.